HVAC systems can be used to regulate the environment within an enclosure. Typically, an air blower is used to pull air from the enclosure into the HVAC system through ducts and push the air back into the enclosure through additional ducts after conditioning the air (e.g., heating or cooling the air). HVAC systems typically include an outside, or condensing unit, and an indoor unit, or air handler with an optional evaporating coil. Air handlers are mounted in an attic, closet, rooftop or basement while condensing units, on the other hand, may be installed on a roof or on the ground. Condensing units typically include a compressor, a condensing coil and a condensing fan. Condensing units, as well as the air handler units of HVAC systems, are vulnerable to transient surges.
To protect against damage from transient surges, industry standards and tests have been developed to characterize surges on AC power circuits. For example, IEEE Standard C62.41.2 provides standardized waveforms and other stress parameters to characterize a surge environment at locations on AC power circuits as described in IEEE Standard C62.41.1. The standardized waveforms can be applied to various electrical devices to determine compliance with the IEEE standard. Typically, the electrical devices, such as HVAC components, are tested to insure compliance with the industry standards. Not all of the tested devices, however, pass the standard tests. As such, changes are often needed to the various failed devices to insure compliance.